A poor sense of smell in older adults is associated with a higher risk of death within a decade or so, according to the NHS.

It comes after a new study, conducted by researchers at the University of Nottingham, suggested that elderly individuals with a weakened sense of smell were likely to have died within 10-13 years - often due to dementia or Parkinson's.

The research, which was funded by the National Institute of Health and National Institute on Aging, involved more than 3,000 participants with an average age of around 75.

Researchers followed participants over several years, analysing and recording health changes - including any deaths.

The study has since attracted significant media attention in the UK - which has now led the NHS to share its own thoughts on such.

So what exactly did the recent study involve? And how did the NHS interpret the researchers' findings?

What was the study?

Participants of the study were aged between 70 and 79, which the NHS says reduces the impact of the findings (Image: Burton Mail)

The research was a cohort study, which involves the identification of a group of people who are then followed over a period of time to see how their exposures affect their outcomes.

In this case, researchers aimed to see whether sense of smell in older adults was linked with risk of dying over the coming years.

Over 3,000 generally healthy participants were recruited in 1997-1998, using a health register in the US, with the group compromised of older adults aged 70-79 who were living in either Pittsburgh or Memphis.

The participants had annual health checks as well as telephone interviews every years - up to 2014.

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During their check in 1999-2000, a total of 2,289 adults completed the 12- item Brief Smell Identification Test - which involved smelling common odours (including chocolate) that participants had to identify from four possible answers.

Researchers followed the health and survival of participants by analysing hospital and morality records - with cause of disease and death documented.

The study looked at the link between smell and these outcomes up to 13 years later, taking account of health and lifestyle factors such as age, smoking history and physical activity levels.

What were the results?

The results show that participants with a poorer sense of smell were more likely to die within 10-13 years than their counterparts (Image: Getty Images)

Over an average 13 years of follow-up, 1,211 participants died - comprising around half of the cohort.

Researchers discovered that those with a poor sense of smell had a 46% higher risk of dying within 10 years and a 30% increased risk within 13 years, than participants with a good sense of smell.

The study however found no link at earlier stages of the follow-up, such as at the five year mark.

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In their analysis of the causes of such deaths, researchers found that poor smell was strongly linked to deaths from Parkinson's disease and dementia, as well as being loosely connected with cardiovascular deaths.

They estimated that, when analysed together, dementia and Parkinson's likely equated to between 25% to 33% of the higher mortality risk.

Researchers concluded that poor sense of smell was associated with higher risk of long-term mortality among older adults - in both men and women as well as across different ethnic groups.

What has the NHS said?

The NHS acknowledged the findings but said more research is needed (Image: Dominic Lipinski/PA Wire)

The NHS acknowledged that the "interesting analysis" found poor sense of smell in older age to be linked with a higher risk of dying within the next 10-13 years.

It however pointed out a number of limitations, including that the average age at the start was 76 - so over the next decade many participants could have died anyway.

"So although the study found poor sense of smell was linked with higher risk," the NHS said, "the absolute change this makes in the person's likelihood of dying might be quite small."

Additionally, despite being a "fairly large study," the NHS questioned however representative such a sample was of the general older population - especially as participants originated in just two cities across the US.

And speculating on the cause behind the study's finding, the NHS said: "It's possible that the development of degenerative change in the brain, as may occur in early dementia for example, could have some effect on the nerves involved with the sense of smell.

"If this is the case, loss of smell might be a potential indicator of a degenerative brain process – but this is pure speculation."

The NHS noted that "there are obviously many other unknown factors involved" though, so further research is necessary.

It also reminded that losing your sense of smell - known as anosmia - can be caused by a number of different conditions, recommending those affected to visit their GP if sense of smell doesn't return within a few weeks.